All the Problems in the World ; ... Because There's No Such Thing as a Stupid Question
What's the hardest substance on earth?
They are forever, a girl's best friend, and, as any pupil will tell you, diamonds are also the hardest substance on earth, right? Well, no - at least not anymore.
Two years ago, a team of physicists at the University of Bayreuth, in Germany, replaced "ice" with the slightly less cool Aggregated Carbon Nanorods (ACNR) as the toughest material known to man.
ACNR, which is 0.3 per cent denser than diamond, was created in a lab by interlocking tiny "nanorods" of carbon. The process involved compressing superstrong carbon molecules called buckyballs to 200 times atmospheric pressure, while heating them to 2,226C.
But how do you measure a material's hardness? Non-scientists use the scratch test, which ACNR passes - it leaves a mark on the toughest diamond - but the official measurement is known as isothermal bulk modulus (the relative change in the volume of a solid as pressure is applied at a constant temperature). Diamond has a modulus of 442 gigapascals, compared to ACNR's 491 gigapascals - the equivalent to the downward force of seven blue whales squeezed into a single stiletto. …